Exhaust means for rotors



Nov. 10, 1936. R. A. NORLING EXHAUST MEANS FOR ROTORS Filed May 2, 1935 R. J 4 Y.

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w Y o NN Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE EXHAUST MEANS FOR ROTORS Application May 2, 1935, Serial No. 19,423

4 Claims.

This invention relates to rotors for portable grinders and other portable rotary tools.

The general purpose and object of the invention is to provide an end exhaust for the rotor chamber as in the end plates of the chamber, whereby the exhaust ports are eliminated from the rotor bushing as heretofore. This reduces bushing breakage as it is unnecessary to drill exhaust holes through the bushings to weaken them, and moreover the bushings last longer bec-ause no opportunity is afforded for the piston elements or blades of the rotors to wear the inner surfaces of the bushings unevenly.

In the accompanying drawing:

Fig. 1 is a side elevational view of a portable grinder having a rotor having an end exhaust in accordance with my invention, the rotor assembly being shown in section and elevation, respectively; and

Figs. 2, 3, and 4 are transverse sectional views taken on lines 2 2, 3 3, and 44, respectively, of Fig. 1 to illustrate details of the rotor construction.

As shown in Fig. 1, the rotor assembly of the tool has a rotor bushing or casing I closed at its opposite ends by end plates 2, 3, which plates provide with the bushing I a rotor chamber d for a rotor 5. The latter, in the construction shown in the drawing, is eccentrically mounted in the bushing I and has contact with the inner surface of the bushing at one portion only in the circumference of the bushing. The rotor 5 is substantially as long as the bushing and has its ends against the end plates 2, 3 as shown.

The piston elements of the rotor are in the form of blades 5, which are carried by the rotor in. radial slots 'l therein. The blades 5 extend the full length of the rotor and the slots 'I are of like length. The slots open through the ends of the rotor and the ends of the blades work against the end plates 2, 3, as shown. The blades have the desired working t in the slots and in the construction shown are forced outwardly of the slots against the inner surface of the bushing I on the pressure side of the rotor to prevent leakage of the pressure fluid from the rear to the front sides of the blades in the operation of the rotor. On the exhaust side of the rotor, the blades are movable into the slots to compensate for the decreasing space between the rotor and the inner surface of the bushing I as the blades approach the contact point between the rotor and the bushing. In the particular construction shown, the blades are forced outwardly on the pressure side of the rotor by connecting the bottoms of the slots to the pressure fluid supply for the tool. On the exhaust side of the rotor, the bottoms of the slots are connected with the exhaust of the rotor. This is accomplis-hed by porting the rotor in advance of each of the slots 1 5 in the manner shown in dotted lines in Fig. 2. As illustrated, the porting comprises pass-ages 5a, 5a which open at their outer ends through the periphery of the rotor in advance of the blades 6 and connect at their inner ends with the bottoms of the slots l for the blades.

The bushing I is supported in a supporting casing 8 and is fixed against rotation therein by key, as shown in Fig. 2 or other suitable holding means. The end plates 2, 3 are clamped against the ends of the bushing in the manner shown in Fig. 1 and are held from turning by being dowelled or otherwise iixedly secured to the bushing I or to the casing 8. The end plates support anti-friction bearings 9, I0 for the shaft extensions II, II with which the rotor 5 is provided at its opposite ends as shown in Fig. 1. The shaft extension il at the front end of the rotor is connected in a suitable manner to the spindle of the tool for rotating the grinding wheel or other working element with which the tool is provided.

The fluid pressure, for example, compressed air, for rotating the rotor is admitted into the rotor chamber 4 through the inlet ports I2 in the bushing I. These ports supply the pressure fluid to the rear sides of the blades i on the pressure side of the rotor and this fluid acting on the blades rotates the rotor. The ports I2 are spaced axial- 1y along the bushing I and connect with a common supply passage I3 which by a port 3' in the end plate 3 connects with a supply groove or channel I4 in the tool head I5 which screws into the casing 8 for clamping the end plates 2 and 3 against the bushing I. The head I5 is provided at its outer or rear end with an inlet fitting I5 for connecting the tool with the source of pressure fluid supply and said head has a suitable passage arrangement indicated generally by i5 for connecting the inlet fitting with the supply groove or channel I4. The head I5 is equipped with a suitable manually operable throttle valve (not shown) for controlling the flow of pressure fluid through the passageway I5" to the rotor of the tool as in structures of this general character.

The exhaust from the rotor chamber 4 is through the end plates 2, 3 in accordance with my invention. This is accomplished by providing each end plate with an exhaust port, marked I6 for plate 2 and I'I for plate 3. These ports extend circumferentially of the rotor chamber and have a length to take in approximately the entire exhaust or low pressure side of the rotor chamber as shown in Figs. 3 and 4. These ports, as shown in these figures, are at the outer edges of the plates, being formed by cutting away the peripheral portions of the plates to the desired extent. V

The exhaust ports I6, I'I are exteriorly of the bushing I and connect with an exhaust chamber I8, which as shown in Fig. 2 comprises the space between the bushing I and its supporting casing 8. This casing has a group of exhaust ports I9 which connect with a chamber 2E] provided by a muffler casing 2i which ts about the casing 8 in spaced relation thereto. The muffler casing 2I is provided with one or more ports 22 which open to the atmosphere, as shown in Figs. l and 4. The muffler casing 2| is suitably secured in place about the outer side of the rotor assembly and may be provided with a number of interior partitions 23 to space the muiiler from the casing S and to provide a tortuous path for the exhaust fluid to silence its discharge from the tool.

With the exhaust means at an end of the rotor chamber and removed from the bushing I, as herein disclosed, the objection to the bushing wearing out and also breaking on account of the exhaust holes drilled in the bushing as herefore, is overcome. The bushing is not weakened as heretofore and moreover a continuous and uninterrupted working surface is provided in the bushing I for the blades. Thus, no opportunity is afforded for the blades to produce a wash board effect in the bushing as heretofore because none of the metal of the bushing is removed in the working surface for the blades. With this surface intact, bushing breakage is reduced and longer lasting bushings result.

As shown in the drawing and more particularly in Fig. 1, it will be noted that the end plates 2 and 3 fit within the casing and have their peripheral edges, except where cut away to provide the exhaust ports I6, I1 in contact with the inner cylindrical surface of the casing 8 beyond the ends of the bushing I. The end plates 2, 3 are clamped against the ends of the bushing I by the casing 8 and the tool head I5. The latter is screwed into the casing 8 against the end plate 3 and clamps said end plate against the adjacent end of the bushing I. The opposite end of the casing 8 has an inwardly extending ange 8a which engages a shoulder 2a on the end plate 2 to draw said plate tightly against the bushing I when the head I5 is tightened against the end plate 3. This provides an effective clamp for the end plates, requiring the use of only one turnable member. The channel I4 in the head I5 connects with the supply passage I3 in any rotative position of the head I5.

The bushing I is supported in the casing 8 by contact with the inner cylindrical surface of the casing along the longitudinal portion Ia of the bushing and at the peripheral edges of its end flanges Ib, Ic and lugs Id. The anges and lugs are duplicated at the opposite ends of the bushing, the flanges being on opposite sides of the 1ongitudinal portion Ia, and the lugs being intermediate the ends of the anges, which terminate at the ends of the adjacent exhaust ports I6, I'I as shown in the drawing. The anges and the lugs are integral with the bushing and project radially outward from the body of the bushing to support the bushing in the casing in the spaced relation required to provide the exhaust chamber I8. The anges and the lugs are co-planar with the ends of the bushing, and have the end plates 2, 3 clamped against them. The end plate 2, as shown in Fig. 2, has a lug portion 2b which seats against the associated bushing lug Id. The peripheral portion of the end plate 2 is cut away on opposite sides of the lug 2b to provide the exhaust port I6. The end plate 3 as shown in Fig. 4, has a lug 3a to seat against its bushing lug Id. The exhaust port I's' in the end plate 3 is formed by reducing the thickness of the end plate on its inner side on opposite sides of and below the lug 3a as indicated in Figs. l and 4. This gives the end plate 3 continuous peripheral contact with the inner surface of the casing 8 to receive the tool head I5 and close the adjacent end of the exhaust chamber I8. The other end of the exhaust chamber I8 is closed by the end plate 2 and the ange 8a of the casing 8.

The key for holding the bushing from turning in the casing 8 is shown at 2Q in Fig. 2. The dowels which connect the end plates to the bushing are shown at 25, 2S in Figs. 3 and 4.

The details of construction and arrangement of parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention, except as pointed out in the appended claims.

What I claim as my invention is:

l. In a motor assembly of the character described, a bushing providing a rotor chamber, a casing surrounding and supporting the bushing and spaced therefrom to provide an exhaust chamber between them, end plates for the opposite ends of the bushing, said end plates tting within the casing beyond the ends of the bushing and having peripheral contact with the casing, means for clamping the bushing in the casing and the end plates against the bushing, a rotor in said bushing and having piston blades engageable with the inner surface of the bushing, and inlet and exhaust ports for the rotor chamber, said inlet ports being in the bushing and said exhaust ports being in the end plates, said exhaust ports being formed in the peripheral portions of the end plates and disposed to connect the exhaust side of the rotor chamber with the exhaust chamber about the opposite ends of the bushing, whereby the inner surface of the bushing is free of exhaust ports to provide a smooth and continuous working surface for the piston blades.

2. In a motor assembly of the character described, a bushing providing a rotor chamber, a casing surrounding the bushing, said bushing having radial end extensions in peripheral contact with the casing to support the bushing in the casing and to space the bushing from the casing to provide an exhaust chamber between them, end plates for the opposite ends of the bushing, said end plates fitting within the casing beyond the ends of the bushing and having peripheral contact with the casing, means for clamping the bushing in the casing and the end plates against the bushing, a rotor in said bushing and having piston blades engageable with the inner surface of the bushing, and inlet and exhaust ports for the rotor chamber, said inlet ports being in the bushing and the exhaust ports being in the end plates, said exhaust ports being formed in the peripheral portions of the end plates, and disposed to connect the exhaust side of the rotor chamber with the exhaust chamber about the opposite ends of the bushing, the end extensions on the bushing being formed to register the exhaust ports with the exhaust chamber.

3. In a motor assembly of the character described, a bushing providing a rotor chamber, a casing surrounding and supporting the bushing and spaced therefrom to provide an exhaust chamber between the bushing and the casing, end plates foin the opposite ends of the bushing, said plates tting within the casing beyond the ends of the bushing and having peripheral contact with the casing, said casing having an inwardly extending portion at one end overlapping and engaging the adjacent end plate, a member screwed into the other end of the bushing against the other end plate for clamping the bushing in the casing and the end plates against the bushing, a rotor mounted in the bushing and having piston blades engageable with the inner surface of the bushing, and inlet and exhaust ports for the rotor chamber, said inlet ports being in the bushing and the exhaust ports being one in each end plate, said exhaust ports being formed by cutting away the peripheral portions of the end plates and disposed to connect the exhaust side of the rotor chamber with the exhaust charnber about the opposite ends of the bushing, whereby the inner surface of the bushing is free of exhaust ports to provide a smooth and continuous working surface for the piston blades.

4. In a motor assembly of the character described, a bushing providing a rotor chamber, a casing surrounding the bushing, said bushing having radial end extensions in peripheral contact with the casing to support the bushing in the casing and to provide an exhaust chamber between the bushing and the casing, end plates for the opposite ends of the bushing, said plates tting within the casing beyond the ends of the bushing and having peripheral contact with the casing, means for clamping the bushing in the casing and the end plates against the bushing, a rotor in said bushing and having piston blades engageable with the inner surface of the bushing, inlet and exhaust ports for the rotor charnber, said inlet ports being in the bushing and the exhaust ports being in the end plates, said exhaust ports being formed in the peripheral portions of the end plates and disposed to connect the exhaust side of the rotor chamber with the exhaust chamber about the opposite ends of the bushing, the exhaust port in one end plate being formed by cutting away the peripheral portion of said end plate, and the exhaust port in the other end plate being formed by reducing the thickness of the end plate on the side facing the bushing, whereby said last named end plate has continuous peripheral contact with the casing.

REINHOLD A. NORLING. 

